#pragma once
#include <etcd/Client.hpp>
#include <etcd/KeepAlive.hpp>
#include <etcd/Response.hpp>
#include <etcd/Watcher.hpp>
#include <etcd/Value.hpp>
#include <thread>
#include <functional>
#include "logger.hpp"

// 服务注册客户端类
class Registry
{
public:
    using ptr = std::shared_ptr<Registry>;

    Registry(const std::string& host)
        : _client(std::make_shared<etcd::Client>(host))
        , _keep_alive(_client->leasekeepalive(3).get())
        , _lease_id(_keep_alive->Lease())
    {}

    bool registry(const std::string& key, const std::string& val)
    {
        auto resp = _client->put(key, val, _lease_id).get();
        if(resp.is_ok() == false)
        {
            LOG_ERROR("注册数据失败: {}", resp.error_message());
            return false;
        }
        return true;
    }

    ~Registry()
    {
        _keep_alive->Cancel();
    }

private:
    std::shared_ptr<etcd::Client> _client;
    std::shared_ptr<etcd::KeepAlive> _keep_alive;
    u_int64_t _lease_id;
};

// 服务发现客户端类
class Discovery
{
public:
    using ptr = std::shared_ptr<Discovery>;
    using NotidyCallback = std::function<void(std::string, std::string)>;

    Discovery(const std::string& host, 
            const std::string& basedir, 
            const NotidyCallback& put_cb, 
            const NotidyCallback& del_cb)
        : _client(std::make_shared<etcd::Client>(host))
        , _put_cb(put_cb)
        , _del_cb(del_cb)
    {
        // 1.先进行服务发现，获取当前的所有服务信息
        auto resp = _client->ls(basedir).get();
        if(resp.is_ok() == false)
        {
            LOG_ERROR("获取键值对数据失败: {}", resp.error_message());
        }
        int sz = resp.keys().size();
        for(int i = 0; i < sz; ++i)
        {
            if(_put_cb) 
            {
                _put_cb(resp.key(i), resp.value(i).as_string());
            }
        }
        // 2.然后进行事件监控，监控数据发生的改变并调用回调函数进行处理
        _watcher = std::make_shared<etcd::Watcher>(*_client.get(), basedir, 
            std::bind(&Discovery::Callback, this, std::placeholders::_1), true);
    }

private:
    void Callback(const etcd::Response resp)
    {
        if(resp.is_ok() == false)
        {
            LOG_DEBUG("收到一个错误的事件通知: {}", resp.error_message());
            return;
        }
        for(auto const& ev: resp.events())
        {
            if(ev.event_type() == etcd::Event::EventType::PUT)
            {
                if(_put_cb)
                {
                    _put_cb(ev.kv().key(), ev.kv().as_string());
                }
                LOG_DEBUG("服务信息新增: {} - {}", ev.kv().key(), ev.kv().as_string());
            }
            else if(ev.event_type() == etcd::Event::EventType::DELETE_)
            {
                if(_del_cb)
                {
                    _del_cb(ev.prev_kv().key(), ev.prev_kv().as_string());
                }
                LOG_DEBUG("服务信息删除: {} - {}", ev.prev_kv().key(), ev.prev_kv().as_string());
            }
        }
    }

private:
    NotidyCallback _put_cb;
    NotidyCallback _del_cb;
    std::shared_ptr<etcd::Client> _client;
    std::shared_ptr<etcd::Watcher> _watcher;
};